[meld] vc: Document a few less-commonly-implemented API points

[Kai Willadsen <kaiw src gnome org>]

commit b39249f321611d5ea2c2cd74fb68912e0aaec255
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sat Feb 6 07:32:56 2016 +1000

    vc: Document a few less-commonly-implemented API points

 meld/vc/_vc.py |   25 +++++++++++++++++++++++++
 meld/vc/git.py |    1 -
 2 files changed, 25 insertions(+), 1 deletions(-)
---
diff --git a/meld/vc/_vc.py b/meld/vc/_vc.py
index 49d21cf..dd91346 100644
--- a/meld/vc/_vc.py
+++ b/meld/vc/_vc.py
@@ -141,12 +141,37 @@ class Vc(object):
         self._tree_meta_cache = {}
 
     def get_files_to_commit(self, paths):
+        """Get a list of files that will be committed from paths
+
+        paths is a list of paths under the version control system root,
+        which may include directories. The return value must be a list
+        of file paths that would actually be committed given the path
+        argument; specifically this should exclude unchanged files and
+        recursively list files in directories.
+        """
         raise NotImplementedError()
 
     def get_commit_message_prefill(self):
+        """Get a version-control defined pre-filled commit message
+
+        This will return a unicode message in situations where the
+        version control system has a (possibly partial) pre-filled
+        message, or None if no such message exists.
+
+        This method should use pre-filled commit messages whereever
+        provided by the version control system, most commonly these are
+        given in merging, revert or cherry-picking scenarios.
+        """
         return None
 
     def get_commits_to_push_summary(self):
+        """Return a one-line readable description of unpushed commits
+
+        This provides a one-line description of what would be pushed by the
+        version control's push action, e.g., "2 unpushed commits in 3
+        branches". Version control systems that always only push the current
+        branch should not show branch information.
+        """
         raise NotImplementedError()
 
     def get_valid_actions(self, path_states):
diff --git a/meld/vc/git.py b/meld/vc/git.py
index 06cf388..65742e1 100644
--- a/meld/vc/git.py
+++ b/meld/vc/git.py
@@ -140,7 +140,6 @@ class Vc(_vc.Vc):
         return sorted(list(set(files)))
 
     def get_commit_message_prefill(self):
-        """This will be inserted into the commit dialog when commit is run"""
         commit_path = os.path.join(self.root, ".git", "MERGE_MSG")
         if os.path.exists(commit_path):
             # If I have to deal with non-ascii, non-UTF8 pregenerated commit